Elucidating Relayed Proton Transfer through a His-Trp-His Triad of a Transmembrane Proton Channel by Solid-State NMR.

ABSTRACT: Proton transfer through membrane-bound ion channels is mediated by both water and polar residues of proteins, but the detailed molecular mechanism is challenging to determine. The tetrameric influenza A and B virus M2 proteins form canonical proton channels that use an HxxxW motif for proton selectivity and gating. The BM2 channel also contains a second histidine (His), H27, equidistant from the gating tryptophan, which leads to a symmetric H¹⁹xxxW²³xxxH²⁷ motif. The proton-dissociation constants (pK_a's) of H19 in BM2 were found to be much lower than the pK_a's of H37 in AM2. To determine if the lower pK_a's result from H27-facilitated proton dissociation of H19, we have now investigated a H27A mutant of BM2 using solid-state

SUBMITTER: Kwon B 

PROVIDER: S-EPMC6589385 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature